[PATCH 6.1.y 1/2] virtio-mmio: Remove virtqueue list from mmio device

[Sasha Levin <sashal@kernel.org>]

From: Viresh Kumar <viresh.kumar@linaro.org>

[ Upstream commit 564a69ad90d15c782176e1a8c9e1c95661e1aed0 ]

The MMIO transport implementation creates a list of virtqueues for a
virtio device, while the same is already available in the struct
virtio_device.

Don't create a duplicate list, and use the other one instead.

While at it, fix the virtio_device_for_each_vq() macro to accept an
argument like "&vm_dev->vdev" (which currently fails to build).

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Message-Id: <3e56c6f74002987e22f364d883cbad177cd9ad9c.1747827066.git.viresh.kumar@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>

[Backport to 6.1: remove the obsolete queue-info declaration without
introducing the notify function pointer from the newer notification-data
support. Keep vm_notify and the existing find_vqs interface. This leaves
the device layout ready for d14d693adb055e98ca705822ba6daebc18602d9a.]

Stable-dep-of: d14d693adb05 ("virtio_mmio: disable IRQ wake before free_irq")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/virtio/virtio_mmio.c | 52 +++---------------------------------
 include/linux/virtio.h       |  2 +-
 2 files changed, 4 insertions(+), 50 deletions(-)

diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 7651940aafd24..7909d4aec8a6e 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -64,7 +64,6 @@
 #include <linux/platform_device.h>
 #include <linux/pm.h>
 #include <linux/slab.h>
-#include <linux/spinlock.h>
 #include <linux/virtio.h>
 #include <linux/virtio_config.h>
 #include <uapi/linux/virtio_mmio.h>
@@ -87,22 +86,8 @@ struct virtio_mmio_device {
 
 	void __iomem *base;
 	unsigned long version;
-
-	/* a list of queues so we can dispatch IRQs */
-	spinlock_t lock;
-	struct list_head virtqueues;
-};
-
-struct virtio_mmio_vq_info {
-	/* the actual virtqueue */
-	struct virtqueue *vq;
-
-	/* the list node for the virtqueues list */
-	struct list_head node;
 };
 
-
-
 /* Configuration interface */
 
 static u64 vm_get_features(struct virtio_device *vdev)
@@ -289,9 +274,8 @@ static bool vm_notify(struct virtqueue *vq)
 static irqreturn_t vm_interrupt(int irq, void *opaque)
 {
 	struct virtio_mmio_device *vm_dev = opaque;
-	struct virtio_mmio_vq_info *info;
+	struct virtqueue *vq;
 	unsigned long status;
-	unsigned long flags;
 	irqreturn_t ret = IRQ_NONE;
 
 	/* Read and acknowledge interrupts */
@@ -304,10 +288,8 @@ static irqreturn_t vm_interrupt(int irq, void *opaque)
 	}
 
 	if (likely(status & VIRTIO_MMIO_INT_VRING)) {
-		spin_lock_irqsave(&vm_dev->lock, flags);
-		list_for_each_entry(info, &vm_dev->virtqueues, node)
-			ret |= vring_interrupt(irq, info->vq);
-		spin_unlock_irqrestore(&vm_dev->lock, flags);
+		virtio_device_for_each_vq(&vm_dev->vdev, vq)
+			ret |= vring_interrupt(irq, vq);
 	}
 
 	return ret;
@@ -318,14 +300,8 @@ static irqreturn_t vm_interrupt(int irq, void *opaque)
 static void vm_del_vq(struct virtqueue *vq)
 {
 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
-	struct virtio_mmio_vq_info *info = vq->priv;
-	unsigned long flags;
 	unsigned int index = vq->index;
 
-	spin_lock_irqsave(&vm_dev->lock, flags);
-	list_del(&info->node);
-	spin_unlock_irqrestore(&vm_dev->lock, flags);
-
 	/* Select and deactivate the queue */
 	writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
 	if (vm_dev->version == 1) {
@@ -336,8 +312,6 @@ static void vm_del_vq(struct virtqueue *vq)
 	}
 
 	vring_del_virtqueue(vq);
-
-	kfree(info);
 }
 
 static void vm_del_vqs(struct virtio_device *vdev)
@@ -363,9 +337,7 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
 				  const char *name, bool ctx)
 {
 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
-	struct virtio_mmio_vq_info *info;
 	struct virtqueue *vq;
-	unsigned long flags;
 	unsigned int num;
 	int err;
 
@@ -382,13 +354,6 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
 		goto error_available;
 	}
 
-	/* Allocate and fill out our active queue description */
-	info = kmalloc(sizeof(*info), GFP_KERNEL);
-	if (!info) {
-		err = -ENOMEM;
-		goto error_kmalloc;
-	}
-
 	num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
 	if (num == 0) {
 		err = -ENOENT;
@@ -446,13 +411,6 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
 		writel(1, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
 	}
 
-	vq->priv = info;
-	info->vq = vq;
-
-	spin_lock_irqsave(&vm_dev->lock, flags);
-	list_add(&info->node, &vm_dev->virtqueues);
-	spin_unlock_irqrestore(&vm_dev->lock, flags);
-
 	return vq;
 
 error_bad_pfn:
@@ -464,8 +422,6 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
 		writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
 		WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
 	}
-	kfree(info);
-error_kmalloc:
 error_available:
 	return ERR_PTR(err);
 }
@@ -610,8 +566,6 @@ static int virtio_mmio_probe(struct platform_device *pdev)
 	vm_dev->vdev.dev.release = virtio_mmio_release_dev;
 	vm_dev->vdev.config = &virtio_mmio_config_ops;
 	vm_dev->pdev = pdev;
-	INIT_LIST_HEAD(&vm_dev->virtqueues);
-	spin_lock_init(&vm_dev->lock);
 
 	vm_dev->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(vm_dev->base)) {
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 82a29db54e7d1..8982611799e0b 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -156,7 +156,7 @@ void virtio_reset_device(struct virtio_device *dev);
 size_t virtio_max_dma_size(struct virtio_device *vdev);
 
 #define virtio_device_for_each_vq(vdev, vq) \
-	list_for_each_entry(vq, &vdev->vqs, list)
+	list_for_each_entry(vq, &(vdev)->vqs, list)
 
 /**
  * struct virtio_driver - operations for a virtio I/O driver
-- 
2.53.0